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RELIABLE L2 ANYCAST FORWARDING BASED ON ARCS

IP.com Disclosure Number: IPCOM000241937D
Publication Date: 2015-Jun-09

Publishing Venue

The IP.com Prior Art Database

Related People

Pascal Thubert: AUTHOR [+3]

Abstract

A solution is provided using anycast technology, to enable switching operations to be performed by setting specific bits, e.g., 2 bits in a Media Access Control (MAC) address, to control Available Routing Construct (ARC) related forwarding. Policies that enable complex functions are also provided.

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RELIABLE L2 ANYCAST FORWARDING BASED ON ARCS

AUTHORS:

   Pascal Thubert Vengada prasad Govindan Mallik Mudigonda

CISCO SYSTEMS, INC.

ABSTRACT

    A solution is provided using anycast technology, to enable switching operations to be performed by setting specific bits, e.g., 2 bits in a Media Access Control (MAC) address, to control Available Routing Construct (ARC) related forwarding. Policies that enable complex functions are also provided.

DETAILED DESCRIPTION

    A layer-2 (L2) fabric may have multiple routers at the fabric edge serving as gateways for a certain service or services. A service may be provided by one or more routers, e.g., a default router, a preferred router for a certain prefix, a preferred router for a certain flow or type of flow, or any combination of the above. A service may also be performed during a certain time of the day, such as during peak traffic hours.

    For each service provided, there may be a number of routers with each router providing one or more services. However, some routers do not provide certain services or do not provide a service at a specified time of day, e.g., some routers do not transport video, do not operate at night, etc.

    The solution utilizes an anycast service, which allows traffic to reach at least one of the routers capable of providing a given service, when one or more L2 links, switches, or routers crashes or is abruptly taken offline. Since the provided services may also depend on the time of day, the solution also includes changing the set of routers during certain periods of the day, and thus, moving a network flow from an initial set of routers to another set of routers without creating a traffic loop.

Copyright 2015 Cisco Systems, Inc.
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    Available Routing Construct (ARC)-based topologies have the capability to perform fast reroute and load balancing over complex destination. This solution provides a novel L2 operation, utilizing ARCanycast Media Access Control (MAC) addresses with embedded control bits.

    As background, a complex destination (e.g., Omega as shown in FIG. 1) may represent a set of edge routers that provide a certain service, which can be flow-type- based, time-based, etc.

    Cascading rules are also defined from an ARCset to another ARCset using a Directed Acyclic Graph (DAG) of services, with the cascading decision based on various factors, e.g., the loss of routing capability for a certain service, the time of day, or whether frames may be rerouted en route in a loopless fashion.

    Additional background is provided with regard to ARC capabilities as follows. An ARC is a 2-ended reversible path, representing a conceptual replacement for a routing segment. Whereas a segment represents a subset of a breakable path, an ARC constitutes its own domain for load balancing and failure recovery, so that at least one failure per ARC may be recovered.

FIG. 1

    As shown in FIG. 1, ARCs may be organized in a set that is referred to as a DAG of ARCs, with the edges of each...